Apparatus having sealing gasket for generation of high pressure



1964 F. WALLIN 3,162,321

APPARATUS HAVING SEALING GASKET FOR GENERATION OF HIGH PRESSURE FiledNov. 29, 1961 2 Sheets-Sheet 1 l6 J2 1540' I Dec. 22, 1964 F. WALLIN3,162,321 APPARATUS HA EALING GASK FOR GENERATI HIGH PRESS Filed Nov.29, 1961 2 Sheets-Sheet 2 IN V EN TOR. Frfiz W/r/iy United States PatentOffice 3,162,321 Patented Dec. 22, 1964 3,162,321 APPARATUS HAVWGSEALING GASKET FOR GENERATION OF HIGH PRESSURE Fritz Wallin, Farsta,Sweden, assignor to Allrnanna Svenska Elelrtriska Aktiebolaget,Vasteras, Sweden, a Swedish corporation Filed Nov. 29, 1961, Ser. No.155,579 Claims priority, application Sweden, Dec. 7, 1960, 11,821/ 60 6Claims- (Cl. 220-46) The present invention relates to an apparatus forgenerating high pressure, in which a space under pressure is limited byparts between which cracks or gaps occur, and the walls of which partsturned towards the space where the cracks or gaps are situated form anangle with each other.

With such pressure apparatus there are great problems in preventingmaterial enclosed in the pressure chamber from leaking out or forcingits way out of the pressure chamber through the cracks or gaps. This isnot only the case with gas and liquid material, but also with solids,particularly if the pressure in the space is great. At high pressure inthe space, solid materials such as, for

. example, rubber or relatively soft metals, for example lead, couldwithout difiiculty flow out through any gaps which may occur.

The invention is based on the use of a specially shaped sealing gasketfor sealing the pressure chamber against the cracks or gaps. It is builtupon the principle that the sealing properties of a gasket will beparticularly good if it is formed so that, when the gasket is inoperation, the pressure at the sealing surfaces, i.e. the contactsurfaces between the gasket and the walls of the parts where the cracksor gaps are situated, is greater than the pressure on the surface of thegasket which is turned towards the pressure chamber. This means that thegasket has an unsupported surface which is situated at the side of thegasket turned away from the pressure chamber. The said principle, basedon the arrangement of the unsupported surface on a gasket, the so-calledBridgmans principle, has been previously utilized in high pressurevessels to eifect a sealing between surfaces parallel with each other,the gasket being arranged between these surfaces. This is seen forexample in Chemie-Ing. Techn. 28 (1956) No. 3, page 142.

gap is situated form an angle with each other. The invention isessentially characterised in that the space under pressure is sealedagainst'the crack or gap by a gasket of rigid material having contactsurfaces on the walls of the parts turned towards the space on bothsides of the crack or gap and a surface-turned towards the inside of thespace, and that the projection of each contact surface of the gasket ina plane perpendicular to the direction of the, resulting pressure forceon the gasket which is derived from the pressure in the space is lessthan the projection in the same plane of half the surface turned towardsthe inside of the space.

The gasket may with advantage be of a rigid metal or metal alloy, forexample of iron, iron alloys of different types such as steel, stainlesssteel, copper or brass.

shape.

In certain cases also, inter alia, rigid plastics may be used asmaterial for the gasket. It is of considerable importance for thefunction of the gasket that it is in itself rigid so that, when it issubjected to pressure from the pressure chamber, it substantiallymaintains its shape and is not notably deformed. The defined relationbetween the projection of each contact surface and the projection ofhalf the surface turned towards the inside of the space will thusprevail when the intended pressure is maintained in the pressurechamber.

The apparatus for generating high pressure may comprise an autoclave ora pressure vessel in which material or materials enclosed in a pressurechamber, under the influence of the pressure, are subjected toalterations in physical properties or shape or undergo chemicalreactions, or a hydraulic press cylinder for a hydraulic press orsimilar apparatus in which cracks or gaps occur between walls forming anangle with each other.

One object of the invention is thus to effect sealing of cracks or gapsin the said apparatus for generating high pressure, so that materialenclosed in the apparatus and subjected to pressure cannot leak outthrough the cracks or gaps.

Another object of the invention is to effect a sealing gasket for anapparatus for generating high pressure in which gaps occur between wallswhich form angles with each other.

The invention will be more closely explained by describing someembodiments chosen by way of example, with reference to the accompanyingdrawing in which FIGURE 1 shows a cross section of an apparatus forgenerating high pressure according to the invention, having cylindricalpressure chamber, FIGURE 2 an enlarged view of the central part of theapparatus according to FIGURE 1, FIGURE 3 an enlarged view of a gasketused in the apparatus according to FIGURE 1 and situated at A in FIGURE2, the cross section of which forms a trapezium, FIGURES 4 and 5alternative embodiments of gaskets which may be used for the apparatusaccording to FIGURE 1.

Referring to FIGURES 1-3, 11 designates a cylindrical pressure chamber.The pressure chamber is limited by a tube 12, forming the envelopesurface of the chamber 11, by a cylindrical plate 13 which lies tightagainst a rigid upper piston 14 having conical form, and by a stamp 15,the upper portion 16 of which has a cylindrical shape and the lowerportion 17 of which has a conical The pate 13 and the portion 16 formthe end surfaces of the cylindrical pressure chamber. The diameter ofthe upper portion 16 is almost as large as the diameter of the pressurechamber. When the pressure apparatus is in use, the stamp 15 isdisplaced inwards into the pressure chamber 11by the movable,substantially conical piston 13 which has an upper cylindrical part 19which fits in the tube 20 which is arranged outside thetub'e 12 in orderto give this support thereto. The tube 20 is surrounded by a pressureabsorbingmember 21, the limiting surfaces 22, 23 and 24 of which areconical and the limiting surfaces 25 and 26 cylindrical. Outermost is astrong mantle 27 having an internally conical shape. By pressing themantle 27 upwards by means not shown, for example a hydraulic press, themember 21 receives an external supporting pressure. A supporting disc 28is arranged above the rigid piston 14, which disc is itself supported bya fixed support, not shown. As is clear from FIGURE 1, the piston 14except for a'minor part thereof, is surrounded by an electricallyinsulating material 29. Around the stamp 15 in the area outside thepressure chamber is arranged a supporting body 30 which surface of thetube 12., The; pressure inthe pressure chamber is-gen'erated by forcingthe stamp int0 the chamber 11L, for example with a hydraulic pressacting on the piston 18- At the sametime as the stamp -15isdisPlacedLupwards the supporting body is subjected to a pressure bythe piston ;18 with its cylindricalj part 19, with the result that thesupporting body supports the stamp, A sealing ring 31 of toughened steelisarranged at the lower edges ofthsupporting body.- Of course, thepiston 14,;just as. the piston 18, can be made movable and provided witha punch ;which can be pushed into the pressure chamber the pressure in;the chamber beinggenerated by forcing both thepunches in. Theobject orthe insulating layer 29 is toenable anelectric ,currentto be led intothe chamber via the bolt 32.- The current is led out through the piston18 and further 1101116 outside of the apparatus where suitable contactsmay be arranged 7, 25

so" that a closed circuit maybe maintained.

In accordance with the invention, the pressure apparatus is providedwith one or several sealing gaskets in the form or rings with openingstherethrough, for example 33 vand 34, of for instance toughened steelsuch as the steel'C550 7 (agents Bruk AB, sweqe a hardness of RG40,which according to the example 'inthe FIGURES 1-3 have a cross section.forming atrapezium. For each gasket, the projection of each of thesu'rfaces constituting,

the Contact portions with the walls-and designated 33a, 33b, 3441v and34b on a plane 332 perpendicular to' the direction of the resultingpressure force (indicatedby arrow 33 which is exercised onleach gasketby the material in thepressure-v chamber 11 (whichrnaterial may consistof, forexamplea mixture of gases, liquidsor solidmatter which is to besubjected to pressure and heat cross section, for example, oneaccordingto FIGURE 4 or one according to FIGURE 5. According to FIGURE4, the gasket 39 has an oval, for example elliptical cross section andaccording to FIGURES the'packing-AO has a cross section which on oneside ,has; a curved and on the other side a straight limiting line. 7

As examples of, materials which may be used for critical parts in highpressure vessels for which the type of material has not been touched.upon, may be mentioned: forthe tube 12, the "stamp 15 and thecylindrical parts 13 and 19, cemented carbide, e.g. Carboloy 999(General Electric Co.)', for the tube 20 a tool steel havingahardness'ofRC 60, ct; C550 (Fagersta Bruk AB, Sweden) or SAE/AISI A2,for the part 2'1, the'mantle 27 and the in order to effect a chemicalalteration); and bythe sup- 7 porting body '30 in the lower pressurechamber, isless than the projection of half the surface turned towardsthe Z respective pressure chambers, i.e. 33c and 34cm each gasket in thesame plane, these, constitutinglimitinglines' ina cross-section cut: bya planecont aining the axis of the "open'ing in the :ring}: Surfaces33c, Me -"aresym-v metrical 'lwith l respect to the bisectors (as33g)iof the V :angle between the walls. i

If the size of'jthe projection in the said plane of surface 332: isdesignated 33A, of surface 33B, 33B, of surface 330, 3C ofsurfac'e'3411, 34A, of surface34b, 34B and of surface'34c, 34C then the condi-'-tion is Y fulfilled that 33A $3C, .33B /233C, 34A V234C and 34B V234CParticularlyf'go'od sealing is i obtained if 33A and 33B areconsiderably smaller than /2'33C,', etc; The surface 33d and 34 are notsupported? The pressure in' the space 11, as in the space where the supporting body :30is situated may'reach not only hundreds and thousands,but even tens of thousands of atmoplieres 60 whi'ch explains thenecessity of a gasket to prevent elastic V fl. A 7 high pressure pistons14. and 18, a tool steel having a hardness of RC55',-'e.g. C550(Fagersta Bruk IAB, 7 Sweden or SAE/AISI A2, and ;for the electricallyinsulating layer 32 mica orpaperl f H In the exemplified cases the highpressure'apparatus is cylindrical; and thus'the gaskets havesubstantially the shape of a circular ring. R is clear'that the pressurechamber has another shape, the gaskets mustbe' fitted to it. If, forexample, the pressure chamber hasparallelepipedic shape, {the gasketswill have substantially the shape of a rectangular frameor strip. 5 1

Iclaim: i I

I apparatus comprising parts having Walls limiting a pressure space,between someof which parts argap may occur, said wallsforming'substantially a right angle with each other where said gap issituated, a solid, gasket of rigid-materialsealing said pressure spacefrom said gap, said gasket having theshape of a continuous frame with acentral opening," said frame having sealing surfaces in contact withsaid walls on both sides of" said gap, the crosssectionof said gasketina plane containing the axis of said opening comprising contact theprojection of each contact'cportion of the gasket on a planejperpendicular to' the.v direction of ,the. pressure exerted on thegasket from Within th e pressure chamber being less than, the projectionon the same plane of half 7, the; limiting line facing theinside of thepressure diameter and one contact portion of the cross section of thegasket 7 being situated nearer to said axis thanjthe other one.

Z High pressure apparatus as clainiedIin claim 1 in which the' crosssection of said gasket has the shape of a trapezium; the longer of the]parallel side ofwhich is material, for example rubber of the typeformingth'e gaps which, may occur.

supporting body 30, from v-flowing through; cracks or a It is:-advaiitageous if the-surfaces3311, 335, 3144 and= 34b are fittedto'the resp'ect'ive;surfaces of thexparts 'in the pressure vessel againstwhich they lie so thatthey seal againstthes'e' evenbeforetthe pressureis, applied, since ing the pressure chamber.

turned towards the inside of; the pressure chamberand thel'egs .ofwhichlie againstthe walls of the parts limit- 3. -High'pressure'apparatus asclairned in claim 1, in

' whichsaid gasket is of a hard metal.

4. High pressure apparatuscornprising a first part havingan inwardlysubstantially cylindrical wall forming the envelope surface of asubstantially cylindrical pressur'echa'mber and asecond part having awall forming atleastpart of an end surface Qf Said'p'r'eSsure' chamber,

the was of said firs't f part sand the wall of said second part formingsubstantially a rightangle with each other where they meet, a solidse'aiing' gasket of rigid v material positioned in the pressure chamberwhere the wall of said otherwise materialgin the respective pressurechambers c aut si tle the sides of the gl'ga'fskets turned ,awayfr'omjthe pressure hambersQ ie. n, the spaces 36c,."3 7 :-[and;;38" that2 thejsurfaces 33d and 1344 will;befsubjected to pressure.- i J T gsket, cor i to t e :inv nt onf qt'tn' d 1 have: the'shap'e A o a-trapezium, but "may have another a-cplane containingihs axislof saidopemngcomprisinga .firstcontact portio'nf'onfthe.wallgiof said firstpart and a first part and. the, wall ofjrsaid second partmeet, for sealing the'pressurelispace against a' gap. which may occur between them,said sealing" gasket having'.-the shape of a substantially circular ringwith a central opening, said I g ringhavingfsea'ling surfaces incontact-avi-thcthe' wallbffi jwould; be ablej to p ass the contact,surfaces-iof' the gaskets 7 with the result that so -much materialwould be collected saidlfirst p art'and with'thewall of 'said secondpart on both sides ofisaid gap,ithe cross section of said-gasket insecond; contact" portion on the Wall "of saidi'second" part and alimitingline facing-theiinside of the pressure chamben andsubstantiallyangren -with respect to, the v bisector of the anglebetween the wall of said first part and the Wall of said second part,the projection of each of said contact portions of the gasket on a planeperpendicular to the direction of the resulting pressure exerted on thegasket from Within the pressure chamber being less than the projectionon the same plane of half the limiting line facing the inside of thepressure chamber and said second contact portion of the cross section ofthe gasket being situated nearer to said axis than said first contactportion.

5. High pressure apparatus as claimed in claim 4 in which the crosssection of said gasket has the shape of a trapezium, the longer parallelside of which is turned towards the inside of the pressure chamber andthe legs of which lie against the walls of the parts limiting thepressure space.

6. High pressure apparatus as claimed in claim 4 in which said gasket isof a hard metal.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS1907 Great Britain.

15 LEWIS J. LENNY, Primary Examiner.

WALTER A. SCHEEL, EDWARD V. BENHAM,

Examiners.

1. A HIGH PRESSURE APPARATUS COMPRISING PARTS HAVING WALLS LIMITING APRESSURE SPACE, BETWEEN SOME OF WHICH PARTS A GAP MAY OCCUR, SAID WALLSFORMING SUBSTANTIALLY A RIGHT ANGLE WITH EACH OTHER WHERE SAID GAP ISSITUATED, A SOLID GASKET OF RIGID MATERIAL SEALING SAID PRESSURE SPACEFROM SAID GAP, SAID GASKET HAVING THE SHAPE OF A CONTINUOUS FRAME WITH ACENTRAL OPENING, SAID FRAME HAVING SEALING SURFACES IN CONTACT WITH SAIDWALLS ON BOTH SIDES OF SAID GAP, THE CROSS SECTION OF SAID GASKET IN APLANE CONTAINING THE AXIS OF SAID OPENING COMPRISING CONTACT PORTIONS ONSAID WALLS AND A LIMITING LINE FACING THE INSIDE OF THE PRESSURE SPACEAND SUBSTANTIALLY SYMMETRICAL WITH RESPECT TO THE BISECTOR OF THE ANGLEBETWEEN SAID WALLS, THE PROJECTION OF EACH CONTACT PORTION OF THE GASKETON A PLANE PERPENDICULAR TO THE DIRECTION OF THE PRESSURE EXERTED ON THEGASKET FROM WITHIN THE PRESSURE CHAMBER BEING LESS THAN THE PROJECTIONON THE SAME PLANE OF HALF THE LIMITING LINE FACING THE INSIDE OF THEPRESSURE DIAMETER AND ONE CONTACT PORTION OF THE CROSS SECTION OF THEGASKET BEING SITUATED NEARER TO SAID AXIS THAN THE OTHER ONE.